Async TCP server with many connections

How to create an async TCP server which can handle many connections without creating a dedicated thread for each one?

-

ReceiveAsync(...)

ReceiveAsync(...)

without

SocketAsyncEventArgs

SocketAsyncEventArgs

is blocking (when being awaited) ->

I guess?
-

ReceiveAsync(...)

ReceiveAsync(...)

with

SocketAsyncEventArgs

SocketAsyncEventArgs

is not blocking ->

I guess?
-

BeginReceive(...)

BeginReceive(...)

does not block and uses the (async) callback mechanism ->

I guess?

Which one to use?